Biogeografia de florestas estacionais deciduais sobre afloramentos calcários em diferentes biomas brasileiros
Carregando...
Arquivos
Data
2020-01-13
Autores
Melo, Pablo Hendrigo Alves de
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Rochas carbonáticas suportam importantes aquíferos, dos quais cerca de 20 a 25% da população mundial depende. No Brasil, essas rochas correspondem a aproximadamente 2,8% da área continental e ocorrem em todos os domínios fitogeográficos. Associadas comumente aos afloramentos de calcários, as Florestas Tropicais Sazonalmente Secas têm a discussão sobre a sua história biogeográfica norteada pelas teorias do Arco Pleistocênico e Floresta Sazonalmente Seca Residual do Pleistoceno. De forma geral, essas teorias propõem que essas florestas constituíam, anteriormente, uma formação extensa e contínua durante o último máximo glacial, entre 18 e 12 mil anos antes do presente. Entretanto, não se conhece a relação de similaridade florística entre afloramentos de calcários em diferentes domínios fitogeográficos, tampouco a relação de similaridade florística entre afloramentos calcários e matriz no entorno. Para investigar essas questões, realizou-se o levantamento florístico de plantas vasculares em 11 afloramentos de calcários na Caatinga, Cerrado e Mata Atlântica. Calculou-se a similaridade florística entre os afloramentos de calcário estudados, bem como entre eles e a matriz no entorno. Por fim, com o auxílio de modelos preditivos de distribuição de espécies, avaliou-se a congruência temporal entre eventos de expansões e/ou retrações de área de distribuição potencial interespecíficos e entre as espécies, com o período de relativa estabilidade da distribuição nas florestas secas do período de 18 a 12 mil anos antes do presente. Os resultados sugerem que a composição florística registrada em afloramentos de calcário na Mata Atlântica foi muito distinta daquelas registradas em afloramentos de calcário na Caatinga e no Cerrado. Com exceção de áreas ecotonais, afloramentos de calcário na Caatinga e no Cerrado apresentaram um fraco relacionamento florístico. A similaridade florística entre os afloramentos dentro do Cerrado diminui significativamente com o aumento da distância geográfica e, no geral, os afloramentos apresentam alta dissimilaridade florística média com a matriz do entorno. Para os modelos, os resultados sugerem que a dinâmica biogeográfica individual das espécies não foi sincronizada com os processos gerais de estabilidade propostos para as florestas secas do período de 18 a 12 mil anos antes do presente, uma vez que três quartos das espécies apresentaram tendência de regressão ou expansão de área de distribuição potencial nesse período. Assim, os resultados corroboram a hipótese de que espécies diferentes não responderam de maneira semelhante às mudanças no clima e permitem concluir que não houve congruência temporal entre eventos de expansões e/ou das espécies no período avaliado.
Carbonatic rocks support important aquifers on which about 20-25% of the world's population depends. In Brazil, these rocks correspond to about 2.8% of the continental area and occur in all Brazilian phytogeographic domains. Commonly associated with limestone outcrops, there is a discussion of the biogeographic history of Seasonally Dry Tropical, guided by the theories of the Pleistocene Arch and Pleistocene Residual Seasonally Dry Forest. Generally, these theories propose that these forests formerly constituted extensive and continuous formation during the last glacial maximum between 18 and 12,000 years before the present. However, the relationship of floristic similarity between limestone outcrops in different phytogeographic domains is not known, nor is the floristic similarity relationship between limestone outcrops in the surrounding matrix. To clarify these issues, a floristic survey of vascular plants was performed in 11 limestone outcrops in Caatinga, Cerrado and the Atlantic Forest. The floristic similarity was calculated between the studied limestone outcrops and between this one and the surrounding matrix. Finally, with the aid of predictive models of species distribution, we evaluated the temporal congruence between events of expansion and/or retraction of interspecific potential distribution area and between species, with the period of relative stability of distribution to dry forests among species between 18 and 12,000 years before the present. The results suggest that floristic composition recorded in limestone outcrops in the Atlantic Forest was very different from those recorded in limestone outcrops in Caatinga and Cerrado. With the exception of ecotonal areas, limestone outcrops in Caatinga and Cerrado showed a poor floristic relationship. Floristic similarity between outcrops within the Cerrado decreases significantly with increasing geographical distance, and in general outcrops present high average floristic dissimilarity with the surrounding matrix. For the models, the results suggest that individual species biogeographic dynamics was not synchronized with the general stability processes proposed for dry forests in the 18 and 12,000 years before the present, since three quarters of the species showed a tendency of regression or expansion of potential distribution area during this period. Thus, the results corroborate the hypothesis that different species did not respond similarly to changes in climate and allowed us to conclude that there was no temporal congruence between expansion and/or species events in the evaluated period.
Carbonatic rocks support important aquifers on which about 20-25% of the world's population depends. In Brazil, these rocks correspond to about 2.8% of the continental area and occur in all Brazilian phytogeographic domains. Commonly associated with limestone outcrops, there is a discussion of the biogeographic history of Seasonally Dry Tropical, guided by the theories of the Pleistocene Arch and Pleistocene Residual Seasonally Dry Forest. Generally, these theories propose that these forests formerly constituted extensive and continuous formation during the last glacial maximum between 18 and 12,000 years before the present. However, the relationship of floristic similarity between limestone outcrops in different phytogeographic domains is not known, nor is the floristic similarity relationship between limestone outcrops in the surrounding matrix. To clarify these issues, a floristic survey of vascular plants was performed in 11 limestone outcrops in Caatinga, Cerrado and the Atlantic Forest. The floristic similarity was calculated between the studied limestone outcrops and between this one and the surrounding matrix. Finally, with the aid of predictive models of species distribution, we evaluated the temporal congruence between events of expansion and/or retraction of interspecific potential distribution area and between species, with the period of relative stability of distribution to dry forests among species between 18 and 12,000 years before the present. The results suggest that floristic composition recorded in limestone outcrops in the Atlantic Forest was very different from those recorded in limestone outcrops in Caatinga and Cerrado. With the exception of ecotonal areas, limestone outcrops in Caatinga and Cerrado showed a poor floristic relationship. Floristic similarity between outcrops within the Cerrado decreases significantly with increasing geographical distance, and in general outcrops present high average floristic dissimilarity with the surrounding matrix. For the models, the results suggest that individual species biogeographic dynamics was not synchronized with the general stability processes proposed for dry forests in the 18 and 12,000 years before the present, since three quarters of the species showed a tendency of regression or expansion of potential distribution area during this period. Thus, the results corroborate the hypothesis that different species did not respond similarly to changes in climate and allowed us to conclude that there was no temporal congruence between expansion and/or species events in the evaluated period.
Descrição
Palavras-chave
Carste, Composição florística, Diversidade beta, Modelos de distribuição de espécies, Último máximo glacial, Floristic composition, Beta diversity, Species distribution models, Last glacial maximum